American Airlines released a statement Sunday night saying, "We are aware of an ongoing security situation at the JFK. There are no known injuries to our employees or passengers at this time and our ticket counter is currently closed. We will provide additional details as they become available."

"At this time, no firearm, rounds or shell casings or other evidence of shots fired has been found," said Joe Pentangelo, a spokesman for the Port Authority of New York and New Jersey Police Department.